Structural, optical and luminescence properties of Sm3+ and Eu3+ doped calcium borophosphate phosphors for reddish-orange and red emitting light applications

Sm3+ and Eu3+ doped calcium borophosphate phosphors with the formula 2CaO-B2O3-P2O5: xRE (where, RE=Sm3+ and Eu3+, x=0.2, 0.4, 0.6, 0.8 and 1.0 mol %) were synthesized by solid state reaction method. 2CaO-B2O3-P2O5: Sm and Eu phosphors were characterized by SEM with EDS, XRD, DRS, excitation, photoluminescence (PL) and decay profiles. SEM results showed that the particles are more irregular morphologies and XRD profiles showed that the prepared phosphors exhibit a hexagonal phase in crystal structure. Using different excitation wavelengths, intense emissions were observed at 403 and 394 nm for Sm3+ and Eu3+ doped 2CaO-B2O3-P2O5 phosphors respectively. The PL measurements showed that the intensity of luminescence increased with increasing doping concentrations upto 0.6 mol% and then decreased at higher concentrations due to the concentration quenching effect for both the ions. From the decay profiles, it was observed that at lower concentrations of Sm3+ (0.2 and 0.4 mol%), the decay curves were well fitted to exponential behavior and for higher concentrations of Sm3+ (0.6, 0.8 and 1.0 mol%), the decay profiles became non -exponential due to the existence of non-radiative channels. In case of Eu3+ ion, decay curves indicated exponential nature for all concentrations. From CIE chromaticity diagram, reddish-orange and red color emissions were observed at 0.6 mol% of Sm3+ and Eu3+ doped 2CaO-B2O3-P2O5 phosphors. (C) 2017 Elsevier B.V. All rights reserved.